Telephone system.



No. 801,864. PATENTED OCT. 17, 1905. v

E. J. HALL. TELEPHONE SYSTEM.

APPLICATION FILED FEB. 8. 1905.

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onirnn STATES PAE UFHQE.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed February 8, 1905. Serial No. 244,684.

To aZZ whom, it may concern.-

Be it known that I, EDWARD J .'HALL, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification, reference being had to the drawing accompanying and forming part of the same.

My invention relates to telephone systems more particularly designed for interior use as, for example, in hotels, dwellinghouses, factories, ofiices. &c., for the purpose of connecting the difierent rooms or departments thereof with a central ofiice and with each other. My system, however, is adapted For both purposes it possesses advantages of simplicity, efficiency, and economy not possessed by any existing system with which I am familiar.

In my system I employ a line-circuit, preferably all metallic, to which the various transmitters and receivers are connected in multiple. Each set of instruments is provided with a call-bell which may be rung by a pushbutton at the central station, the bell-circuit for a particular station or set of instruments being formed by a separate wire thereto with one of the wires of the line-circuit as a common return. The various bell-wires are connected to the contacts of a switchfor example, a switch of the ordinary lever type while the switch -lever is tapped onto the common return. The battery for ringing the bells and for talking purposes is connected in the common return-wire between the point where the switch-lever is tapped in and the various stations of the system. In the tap to the switch-arm is a push-button, so that by throwing the lever to the proper contact the central operator canby pressing his button call any desired station. On the other hand, the call-bell at central is not in circuit with the switch, but is connected across the linewires, while at each station there is a pushbutton similarly connected. Hence any station can ring centrals hell no matter what position the latters switch may be. The callbells are all connected through the hookswitches of the respective instruments, so that the removal of the receivers from. the hooks by the users cuts out the bells and connects the telephone instruments with the talking wires. WVhen one station desires to talk with another, the first calls central and gives the operator the number in the usual way. Central then moveshis switch to the desired number and rings the latters bell. Removal of the latters receiver from its hook connects him with the line-wires, and the two stations are immediately in connectionand able to talk.

The invention itself, which consists in the novel features, combinations of elements, and arrangements of parts hereinafter described,

and more particularly set forth in the claims,

is shown diagrammatically in the accompanying drawing, which illustrates the preferred embodiment.

The line or talking wires of the system are indicated by W WV, and across these are bridged all the telephones included in the installation. The system illustrated provides for four substations, (only two of which are shown, however, indicated by 1 and 4, respectively;) but a greater or less number may be included, as will appear more fully hereinafter. One of the line wires, as W, is connected with all the hooks /t it if, while the other wire W is connected to the transmitters and receivers T R, T R, T R and through them to the upper contacts of the hook-switches. The call-bell B at the central station C is connected to wire W and through the lower contact of the hook-switch it to the other line-wire W. The battery S is connected in the latter wire, as shown, so that centrals bell Will be rung so long as thehook 7t rests in the lower contact whenever the line circuit N W is completed. For the latter. purpose each substation is provided with a push-button connected across the taps which connect the transmitter and receiver with the line-wires. Thus in the case of station 1, for example, if the button a is pressed the circuit will be established through tap 0, line-wire W, wire 0, bell B, hook it, wire 0 battery S, Wire W, wire 0 back to button a. It will be noted that this circuit is independent of the hookswit'ch of the substation, so that it is not necessary for the latter to leave his receiver on the hook before pressing his signal-button, but may remove the receiver first and so be able to hear centrals reply at once. As soon as central responds to the signal by removing his receiver the circuit above described is broken by the hook it rising against its upper contact. The talking-circuit is thereby established as follows: transmitter T, hook it, wire 0 line-wire W, battery S, wire 0 .hook it, transmitter T, receiver R, wire W, wire 0, receiver R, back to transmitter T.

It will be noted that the bell and other instruments of station 4 are not included in either of the circuits traced, so that the last-mentioned station (and the same is in any case of course true of all other stations except the one which has called central) has no intimation that anything is going on over the system. When central and the calling station have finished their conversation, the replacing of centrals receiver on its hooks restores the system completely to its former condition so far as concerns station ls ability to call the former, though, as will appear hereinafter, the substation cannot be called by central unless the formers receiver is hung up. I

The circuit for calling a substation fro central will now be described, taking station 1 as an example. I) Z2 Z2 indicate bell-wires connected to separate contacts at the central switch S. Each bell-wire is connected also to a substation-bell. Thus in the case of station'l the bell B is connected to wire 5 and through hook it to line-wire W. The lever of switch S is connected to the battery S by a wire 0 and in the latter is a push-button a. Supposing now that central'desires to call station 1, the operator turns hisswitch to wire bs contact and presses button a, whereupon a circuit is established through switch S, wire 5, wire 0*, bell B, hook it, wire 0 wire W, battery S, and wire 0", back to button a. It will be noted that this circuit does not include centrals hook-switch, so that the operator may remove his receiver before signaling the station, and hence may be ready to hear the reply at once. This is, also true, as previously explained, of a substation when the latter desires to call central, and it will therefore be seen that the signaling-button of any station, central or substation, is independent of the bell and telephone instruments at such station, so that the person calling may signal the other station either before or after placing his receiver to his car.

As soon as the person at station 1 takes his receiver from its hook to answer centrals ring the hook h rises, breaking the circuit through bell B traced above, and centrals receiver being also removed the talking-circuit previously described is established through transmitter T, hook it, wire 0 .battery S, wire W, wire 0", book it, transmitter T, receiver R, wire 0, wire W, and receiver R back to transmitter T. On conclusion of the conversation the parties hang up their receivers, thereby restoring the system to its original condition, putting the various pushbuttons in circuit with their respective bells. Central, however, may leave the switch S or whatever contact it happens to be on, since centrals bell and the buttons at the substations for ringing the same are not connected through the switch S, but through the linewires W W and hook 72., so that as long as centrals receiver is on its hook the operator may be called by any substation irrespective of the position of switch S. It is only when central desires 'to call a substation that the switch is brought in use.

If a substation, having called central, desires to talk with another'station, central simply places his switch-lever at the desired number and pressesbutton (0. Thus, assuming that station 1 desires to talk with No. 4:, central turns the switch to No. ts contact, and on pressing button a the circuit is established through bell B in a manner similar to that described in the case of station 1. As soon as No. 4 takes down his receiver the circuit through bell B is broken and his telephone is connected with the talking-wires W W ready for conversation with No. 1.

The system described above possesses numerous advantages. In the first place it is very simple. Its switchboard is merely a le- -ver moving over a series of contacts, thus avoiding the employment of the complicated apparatus now commonly in use, with its attendant defects of delicacy and liability to get out of order, necessity of frequent inspection and repairs, &c. No annunciator is needed, and there are no drops or similar devices to be restored by central operator after using. The operator does not need to have any special training or skill, as the manipulation of a simple lever-switch and pressing a button are all the operations involved in calling a station and the mere replacement of receivers after conversation is finished restores the system to its normal condition, it being unnecessary to restore the switch to some particular position before central can be signaled by a subscriber. The system can be installed on any existing annunciator system, making special wiring unnecessary in such cases. It is a central-energy system, requiring but slight expense for battery when installed and entirely obviating battery trouble at the substations. The same battery is used for both signaling and talking. As will be noted in the drawing, the cells are connected in series multiple, giving strong current for signaling, yet with sufficient amperage for talking, so that conversation is very distinct, all without the use of induction-coils. Only two breaking contacts at each hook-switch are used, thus avoiding defects so commonly met with in apparatus employing a complicated arrangement of contacts. Central can call any station, and vice versa, and without the calling party doing so before removing his receiver from its hook. This is an important ad vantage in avoiding confusion and delay in using the system. Any substation can talk with any, other merely by calling central, who simply places his switch at the desired number and calls the party.

The systems field of use for interior purposes is practically unlimited, being particularly adapted by reason of its simplicity,

efiicien'cy,and economy for apartment-houses, hotels, and factories.

The arrangement herein specifically shown and described is, of course, only one of the different embodiments of which the invention is capable without departure from its proper scope.

What I claim is- 1. In a telephone system comprising a cen tral station and substations, the combination of common line-wires constituting a line-circuit; telephones at the stations, having hookswitches with upper and lower contacts, the telephones being connected to the said upper contacts and one of the line-wires, the hookswitches being connected to the other linewire; a signaling device at the central station, connected to the lower contact thereat and the line-wire to which the telephones are connected; a battery in the line-circuit; and means at each substation for closing the line-circuit to actuate the said signaling device; as set forth.

2. In a telephone system comprising a central station and substations, the combination of common line-wires constituting a line-circuit; telephones at the stations, having hookswitches with upper and lower contacts, the telephones being connected to the said upper contacts and one of the line-wires, the hookswitches being connected to the other linewire; a signaling device at the central station, connected to the lower contactthereat and the line-wire to which the telephones are connected; means at each substation for closing the line-circuit to actuate the said signaling devices; a plurality of signalwires extending from the central to the sub stations;

a signaling device at each substation, connected to one of the signal-wires and the lower contact thereat; means at the central station for completing a signaling-circuit through any of the signal-wires and the substation signaling device connected thereto; and a battery common to the line-circuit and the signalingcircuits; as set forth.

3. In a telephone system comprising a central station and substations, the combination of common line-wires constituting a line-circuit; telephones at the stations, having hookswitches with upper and lower contacts, the telephones being connected to the said upper contacts and one of the line-wires, the hookswitches being connected to the other linewire as a common return; a signaling device at the central station, connected to the lower contact thereat and the line-wire to which the telephones are connected; means at each substation for closing the line-circuit to actuate EDWARD J. HALL.

Witnesses:

M. LAwsoN D ER," S. S. DUNI-IAM. 

